A disconnector is a switching device that could provide, at an opening position, an insulation distance between contacts conforming to specified requirements and a distinct disconnection sign and could withstand, at a closing position, currents under a normal circuit condition and currents under an abnormal condition (e.g., short circuit) within a specified time. The disconnector is an important switching device in an electrical power system and its primary function is to ensure safety during maintenance of high-voltage electrical devices and apparatuses and to isolate the voltage.
In high latitude areas, such as northern cold regions, the temperature is quite low in winter and the operating environment is harsh. The ice and snow that cover the outdoor disconnector for a long time will impact reliability of opening and closing actions of the switch, such that contacts of the disconnector are separated by ice and cannot be completely conducted, which disables operations and threatens operation of electrical power systems and safety of power grids.
To solve the ice coating issues, the existing disconnector, while closing, usually enables the contact to have ice-breaking functionality. For example, when the moving contact and the static contact of the disconnector are being closed, a clamping and sliding procedure occurs to break the ice layer. However, this method for breaking the icing with an increased clamping force of the contact can only break the icing of a certain thickness, and cause wear of contacts, increase in operating force and a higher rigidity requirement. Besides, it also increases output torque of mechanisms and has a defect of higher costs. In the northern cold regions, the outdoor disconnector might be covered with an ice layer of up to 20 mm or more, whereas the existing disconnector can hardly ensure normal operations even in an environment with icing of 10 mm. Thus, it might impact operation of electrical power devices in a cold and freezing environment and cannot ensure safe and stable operations of the entire electrical system. The high-voltage disconnector even cannot open or close when the icing is heavy.
In order to solve this problem, the prior art also provides a light energy ice-breaking auxiliary arrangement. That is, solar energy is gathered and incident to a light-to-heat converter to convert light energy to thermal energy and achieve a purpose of breaking ice by heating. However, this light energy ice-breaking auxiliary arrangement and the heat ice-breaking auxiliary arrangements based on other principles have complex structure and lower reliability, and thus cannot meet needs of actual operations.
To satisfy the usage requirements of disconnector in northern cold regions, an outdoor disconnector with anti-icing function is in urgent need in the prior art, which still can perform reliable mechanical operations when the ice layer reaches a thickness of 20 mm at most.